It has been well established that consumption of red and processed meats increases the risks of developing colorectal cancer, as well as other negative health effects in humans. Specifically, studies have found that people should not eat more than 500 grams of red meat (cooked) per week, and should avoid processed meats entirely. In these meats, heterocyclic amines (HAs) are present, some of which are known to be carcinogenic in animals (including PhIP, MeIQx, and 4, 8-DiMeIQx).
Some studies have found that by adding antioxidants, the formation of these carcinogenic HAs is inhibited. Specifically, these studies have examined antioxidant protection from tart cherry tissue, carotenoids from tomatoes, fruit extracts, or various spices. One extract in particular, grape seed extract, is known to have very high antioxidant capacities, and therefore is a viable option for inhibiting the formation of HAs in the food industry.
The goal of the study presented today was to determine the ability of water-in-oil marinades containing grape seed extracts to reduce the HA content in beef patties. Marinades were chosen due to their known ability to reduce HA content in meats, according to some studies.
Frozen beef patties were approximately 70 grams and measured 8x113x105mm.
Grape seed extract was produced by water extraction and spray drying. The extract was then dissolved in ultrapure water, filtered, and then used in the marinades using the following amounts: 0.2g, 0.4g, 0.6g, and 0.8g per 100g water-in-oil emulsion.
Water in oil emulsions were created by homogenizing 67.5 grams of sunflower oil, 0.5 grams of an emulsifier (citric acid esters of mono- and diglycerides of fatty acids) and 32 grams of the diluted grape seed extract. The emulsions were set to marinade with the beef patties immediately after manufacturing. Water-in-oil emulsion controls without grape seed extract were also included in the study.
Beef patties were fried on two plates of a double contact grill that was preheated to 230oC. Frozen patties were coated with 1.5 grams of refined sunflower oil alone or water-in-oil emulsions with or without the grape seed extract on both sides. Patties were then covered on both sides with aluminum foil. Patties were fried for 2 minutes and 40 seconds, a time which has been established to result in acceptable sensory character in beef patties. For each treatment, 8 patties were fried and homogenized for chemical analysis. For sensory analysis, 8 patties were fried (after marination) and divided into four pieces each.
The following were measured/analyzed for all treatments: antioxidant capacity, total phenolic content, concentrations of HAs, beef patty weight loss, creatine content, and glucose levels.
For the sensory analysis, 8 panelists were selected and trained to analyze sensory characteristics of beef in this type of marinade system. Sensory characteristics were ranked on a hedonic scale, ranging from 1 (best color and/or flavor) to 6 (worst color and/or flavor). Panelist also described any potential negative color or flavor characteristics.
- Beef patties broke down into the following components: 61.1g/100g moisture, 0.72g/100g minerals, 21.2g/100g fat, 17.6g/100g protein, 0.293g/100g hydroxyl proline, and 0.84g/100g glucose.
- Beef patties were found to contain the HAs MeIQx, PhIP, and the co-mutagenic β-carbolines Norharman and Harman.
- The highest amount of grape seed extract present in the marinades (8g/kg) resulted in a reduction in MeIQx of 68% and a reduction in PhIP of 90%.
- Increased amounts of grape seed extract in the marinades led to increased concentrations of the β-carbolines Norharman and Harman.
- There were no significant differences between patty weight loss in the control samples versus the samples marinated in grape seed extract.
- Patties pretreated with grape seed extract were significantly darker at the highest concentration of extract that all other samples (8g/kg).
- Compared to rosemary extract (which was also studied in this paper but not presented for the purpose of this blog’s theme), grape seed extract had a significantly higher antioxidant activity.
- Total phenolic content in grape seed extract was 26 times higher than in rosemary extract.
- Linear correlation analysis suggested that formation of the HAs MeIQx and PhIP are dependent upon the antioxidant capacity of the extract.
- Sensory analysis found no differences between control beef patties and beef patties marinated in grape seed extract.
o Both color and flavor were not significantly different between these treatments.
The results of this study indicate that levels of the two carcinogenic HAs that were found in frozen beef patties, MeIQx and PhIP, were significantly reduced after a marinade treatment containing grape seed extract. This result is likely due to the fact that grape seed extract contains high concentrations of antioxidants, which are effective free radical removers and thus overall effective HA reducers.
By looking at water and oil as bases for the beef patties marinades, the authors determined that the solubility of the grape seed extract components were not as important as the total phenol and antioxidant content of the marinades. In addition to antioxidants, according to the authors it is possible that other compounds are playing important roles in the reduction and inhibition of HAs, including hexose and pentose, the effects of which warrant further study.
Overall, the results of this study indicate that using grape seed extracts in beef patty marinades is an effective pretreatment prior to the cooking process, since it significantly reduces the levels of carcinogenic HAs in the meat as well as having no effect on the sensory characteristics of the finished hamburger. It is possible that this pretreatment may be recommended to restaurants that cook significant numbers of beef patties (including fast food chains) and also possibly the pretreatment of meat going to grocery stores and specialty shops.
I’d love to hear what you all think about this topic! Would you like to have seen the authors perform any other types of analysis? Please feel free to leave your comments below!
Source: Gibis, M., and Weiss, J. 2012. Antioxidant capacity and inhibitory effect of grape seed and rosemary extract in marinades on the formation of heterocyclic amines in fried beef patties. Food Chemistry 134: 766-774.
I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!